Patents by Inventor Donald David Theobald

Donald David Theobald has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Patent number: 3973328
    Abstract: A method and apparatus for drying polyethylene laminated base photographic paper in sheet form. The exposed and processed sheet of photographic paper bearing a photographic image on one side thereof is caused to travel through an enclosed drying chamber. Radiant heat is directed from sources onto both sides of the sheet of photographic paper as it is caused to travel through the drying chamber. The radiant heat is applied for sufficient time to cause any shallow indentation lines on the image side of the photographic paper to disappear. Simultaneously a stream of cool air is caused to flow over the image side of the photographic paper. Both sources are provided with means for directing the radiant heat on to each side respectively of the support.
    Type: Grant
    Filed: April 22, 1974
    Date of Patent: August 10, 1976
    Assignee: Ilford Limited
    Inventor: Donald David Theobald